Acoustic emission monitoring to study sodium sulphate crystallization in monumental porous carbonate stones

Abstract

Soluble salts inside porous stone can induce stresses. Under these circumstances, elastic waves (acoustic emission/microseismic activity, AE/MS) can be generated spontaneously. In the present study, acoustic emission monitoring of salt crystallization tests performed on monumental stones was carried out in order to determine the deterioration processes occurring during the test. The studied materials were porous carbonate stones from Spanish monuments with different porosity and pore opening radius distribution. Sodium sulphate was the selected salt. AE/MS recorded during the different cycle stages (immersion, drying and cooling) was related to sodium sulphate characteristics and pore space characteristics of the stones.